Argo CD with GitLab CI, Part 3: Setting Up Argo CD, Argo CD CLI and CoreDNS

# Create a Kubernetes namespace named "argocd" for Argo CD installation
kubectl create namespace argocd

# Deploy Argo CD in the "argocd" namespace
kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml

# List the Argo CD resources
kubectl get all -n argocd

# Change the Argo CD Service service to type LoadBalancer
kubectl patch svc argocd-server -n argocd -p '{"spec": {"type": "LoadBalancer"}}'

# List Argo CD serivce details
kubectl describe service argocd-server -n argocd

# Update the TLS Kubernetes secret
kubectl create -n argocd secret tls argocd-server-tls \
  --cert=fullchain.pem \
  --key=privkey.pem

# Create a DNS entry
192.168.30.201 argocd.jklug.work

# Access the webinterface: Via LoadBalancer service
https://argocd.jklug.work

# Default user
admin

# Retrieve "admin" password
kubectl get secret argocd-initial-admin-secret -n argocd -o jsonpath="{.data.password}" | base64 --decode; echo

# Shell output:
jchy00fSWDPqA375

# Delete the "argocd-initial-admin-secret" secret
kubectl delete secret argocd-initial-admin-secret

# Download Argo CD binary (This takes a while)
curl -SL --progress-bar -o argocd https://github.com/argoproj/argo-cd/releases/download/v2.12.7/argocd-linux-amd64

# Change permissions
chmod +x argocd

# Move the binary
sudo mv argocd /usr/local/bin/

# Verify the installation / check version
argocd version

# Shell output:
argocd: v2.12.7+4d70c51
  BuildDate: 2024-11-05T15:52:38Z
  GitCommit: 4d70c51e64e534ffe656c45317037b2bcdaa69f9
  GitTreeState: clean
  GoVersion: go1.22.8
  Compiler: gc
  Platform: linux/amd64
FATA[0000] Argo CD server address unspecified

# Add DNS entry to /etc/hosts
sudo tee -a /etc/hosts <<EOF
192.168.30.201 argocd.jklug.work
192.168.70.4 gitlab.jklug.work gitlab-registry.jklug.work
EOF

# Set the the Argo CD server address
argocd login argocd.jklug.work


# Shell output:
Username: admin  # Enter default admin user
Password: jchy00fSWDPqA375  # Enter the admin pw
'admin:login' logged in successfully
Context 'argocd.jklug.work' updated

# Add DNS entry to /etc/hosts
sudo tee -a /etc/hosts <<EOF
192.168.70.4 gitlab.jklug.work
192.168.70.4 gitlab-registry.jklug.work
EOF

# Export the current ConfigMap
kubectl get cm coredns -n kube-system -o yaml > coredns-configmap-backup.yaml

# Add the following DNS section to the CoreDNS ConfigMap
hosts {
    192.168.70.4 gitlab.jklug.work
    192.168.70.4 gitlab-registry.jklug.work
    fallthrough
}

# Edit the CoreDNS ConfigMap
kubectl edit cm coredns -n kube-system

# Please edit the object below. Lines beginning with a '#' will be ignored,
# and an empty file will abort the edit. If an error occurs while saving this file will be
# reopened with the relevant failures.
#
apiVersion: v1
data:
  Corefile: |
    .:53 {
        errors
        health {
           lameduck 5s
        }
        ready
        kubernetes cluster.local in-addr.arpa ip6.arpa {
           pods insecure
           fallthrough in-addr.arpa ip6.arpa
           ttl 30
        }
        hosts {
            192.168.70.4 gitlab.jklug.work
            192.168.70.4 gitlab-registry.jklug.work
            fallthrough
        }
        prometheus :9153
        forward . /etc/resolv.conf {
           max_concurrent 1000
        }
        cache 30
        loop
        reload
        loadbalance
    }    
kind: ConfigMap
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
            {"apiVersion":"v1","data":{"Corefile":".:53 {\n    errors\n    health {\n       lameduck 5s\n    }\n    ready\n    kubernetes cluster.local in-addr.arpa ip6.arpa {\n       pods insecure\n       fallthrough in-addr.arpa ip6.arpa\n       ttl 30\n    }\n    prometheus :9153\n    forward . /etc/resolv.conf {\n       max_concurrent 1000\n    }\n    cache 30\n    loop\n    reload\n    loadbalance\n}\n"},"kind":"ConfigMap","metadata":{"annotations":{},"creationTimestamp":"2024-11-23T11:51:59Z","name":"coredns","namespace":"kube-system","resourceVersion":"253","uid":"7780f5a2-09c9-418c-b139-43231097afe7"}}
  creationTimestamp: "2024-12-06T11:27:57Z"
  name: coredns
  namespace: kube-system
  resourceVersion: "12187"
  uid: 4c18c50e-fba5-4335-8431-2bf1cd31ef01

# Restart CoreDNS
kubectl rollout restart deployment coredns -n kube-system

# Run a busybox pod
kubectl run busybox --image=busybox --restart=Never --stdin --tty

# Test the GitLab DNS resolution
nslookup gitlab.jklug.work

# Shell output:
Server:         10.96.0.10
Address:        10.96.0.10:53


Name:   gitlab.jklug.work
Address: 192.168.70.4


# Exit the container terminal
exit

# Delete the busybox pod
kubectl delete pod busybox